U.S. Pat. No. 4,009,921, issued to Narozny on Mar. 1, 1977 and commonly assigned with the invention herein, sets forth a connector having a housing supporting insulation-piercing electrical contact elements in laterally spaced longitudinally extending rows mutually staggered to register with the individual conductors of flat multiconductor cable. At ends distal from the insulation-piercing portions thereof, the contact elements define resilient portions situated outwardly below the housing and adapted to register with conductive strips supported on the surface of a PCB. The housing includes dependent legs insertable through openings in the PCB and engageable with the PCB undersurface both to retain the housing upon the PCB and to apply compressive force to the contact resilient portions whereby these portions are placed in low resistance engagement electrically with the PCB strips. A suitable transition from the conductors of the flat cable to the PCB strips may thus be provided over limited contact element successions, i.e., when extended contact element successions are involved, PCB warpage may serve to adversely lessen contact element and strip contact engagement uniformity. Thus, where PCB warpage occurs, higher electrical resistance is introduced as respects the longitudinally outward contact elements and strips, giving rise to less than desired connection effectiveness.
The connector of the '921 patent and various other known PCB-mountable connectors do not have sufficiently large anti-PCB warpage capabilities to meet extended contact element successions, based in a large measure upon the fact that these connectors apply force to the substrates at longitudinally opposite ends of the connector. Indeed, this characteristic is necessitated at least in part by the requirement that the intrusion of the connectors on the PCB be limited, as respects openings formed therein for connector receipt, since such openings themselves lessen substrate strength and anti-warpage character.